body {
    margin: 0px;
    padding: 0px;
    background-image: url('images/timg.jpg');
    background-size: 100%;
    background-repeat: repeat;
    background-size: cover;
    text-align: center;
}

p {
    margin: 0;
    padding: 0;
}

.flex-container {
    background-size: 100% 100%;
    background-attachment: fixed;
}

.center {
    display: block;
    margin-left: auto;
    margin-right: auto;
    margin-top: auto;
    margin-bottom: auto;

}

.button_left {
    position: absolute;
    left: 410px;
    width: 100px;
    padding: 4px;

}



.node {
    cursor: auto;
}

.node circle {
    fill: rgb(174, 53, 164);
    stroke: rgb(224, 124, 9);
    stroke-width: 3px;
}

.node rect {
    fill: #800000;
    stroke: #800000;
    stroke-width: 5px;
}

.node text {
    font: 12px "楷体", sans-serif;
}

.link {
    fill: none;
    stroke: rgb(28, 235, 166);
    stroke-width: 2px;
}

#title {
    text-align: center;
    color: rgb(73, 26, 245);
    font: 30px "楷体", sans-serif;
    font-weight: normal;
    line-height: 70px;
    text-shadow: rgb(34, 34, 34) 2px 2px 3px;
    background: rgb(243, 111, 49);
}